UE4Editor_Engine!UEdGraphPin::SerializePin() [edgraphpin.cpp:1497] UE4Editor_Engine!UEdGraphPin::SerializePinArray() [edgraphpin.cpp:1393] UE4Editor_Engine!UEdGraphPin::Serialize() [edgraphpin.cpp:1249] UE4Editor_Engine!UEdGraphPin::SerializePin() [edgraphpin.cpp:1535] UE4Editor_Engine!UEdGraphPin::SerializePinArray() [edgraphpin.cpp:1393] UE4Editor_Engine!UEdGraphNode::Serialize() [edgraphnode.cpp:317] UE4Editor_BlueprintGraph!UK2Node_CallFunction::Serialize() [k2node_callfunction.cpp:1819] UE4Editor_UnrealEd!FTransaction::FObjectRecord::SerializeContents() [editortransaction.cpp:137] UE4Editor_UnrealEd!FTransaction::FObjectRecord::Load() [editortransaction.cpp:178] UE4Editor_UnrealEd!FTransaction::Apply() [editortransaction.cpp:444] UE4Editor_UnrealEd!UTransBuffer::Undo() [editortransaction.cpp:855] UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper<void> __cdecl() [delegateinstancesimpl.h:317] UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl() [delegateinstancesimpl.h:423] UE4Editor_Slate!FUICommandList::ConditionalProcessCommandBindings() [uicommandlist.cpp:211] UE4Editor_Slate!FUICommandList::ProcessCommandBindings() [uicommandlist.cpp:155] UE4Editor_UnrealEd!FBaseToolkit::ProcessCommandBindings() [basetoolkit.cpp:77] UE4Editor_UnrealEd!SStandaloneAssetEditorToolkitHost::OnKeyDown() [sstandaloneasseteditortoolkithost.cpp:335] UE4Editor_Slate!<lambda_2afcd964c763e269e2d1a63f3a72f846>::operator() [slateapplication.cpp:4517] UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FKeyEvent,<lambda_2afcd964c763e269e2d1a63f3a72f846> >() [slateapplication.cpp:215] UE4Editor_Slate!FEventRouter::RouteAlongFocusPath<FEventRouter::FBubblePolicy,<lambda_2afcd964c763e269e2d1a63f3a72f846>,FKeyEvent>() [slateapplication.cpp:197] UE4Editor_Slate!FSlateApplication::ProcessKeyDownEvent() [slateapplication.cpp:4515] UE4Editor_Slate!FSlateApplication::OnKeyDown() [slateapplication.cpp:4430] UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [windowsapplication.cpp:1419] UE4Editor_Core!FWindowsApplication::DeferMessage() [windowsapplication.cpp:1930] UE4Editor_Core!FWindowsApplication::ProcessMessage() [windowsapplication.cpp:747] UE4Editor_Core!FWindowsApplication::AppWndProc() [windowsapplication.cpp:669] user32!<Unknown> user32!<Unknown> UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [windowsplatformmisc.cpp:905] UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:2788] UE4Editor!GuardedMain() [launch.cpp:156] UE4Editor!GuardedMainWrapper() [launchwindows.cpp:126] UE4Editor!WinMain() [launchwindows.cpp:202] UE4Editor!__scrt_common_main_seh() [exe_common.inl:264] kernel32!<Unknown> ntdll!<Unknown>
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-34564 in the post.